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DEALING WITH THE LEGACY OF

Asbestos may seem like a nasty problem of the past, but half the word still uses it. The other half has banned it, but its legacy in old buildings remains. Anthony King reports

DOI:10.1002/cind.816_6.x

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Mined from the ground since ancient times, asbestos is a class of six naturally occurring silicate minerals. All types are made up of fibrous crystals, each of which is composed of millions of small fibrils that can be released by abrasion or other similar processes.

Large-scale industrial mining of asbestos began towards the end of the 19th century predominantly in Russia, China, Kazakhstan and Brazil. This relatively cheap material with excellent fire and heat resistance, good electrical insulating properties and

high tensile strength was used widely in the construction industry, and in many other products, including brake pads, hair dryers and industrial filters for wine, beer and pharmaceuticals.1 The most commonly used asbestos is chrysotile or white asbestos, which accounts for around 95% of all asbestos used worldwide. An estimated 2m t of asbestos continue to be used each year globally.2

But asbestos exposure can be deadly. Anyone who handles the material or breathes in its fibres puts themselves at risk of lung diseases such as asbestosis and cancer. The

PHOTO INSOLITE REALITE/SCIENCE PHOTO LIBRARY

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asbestos is not responsible for all cancers and questions the safety of substitute fibres.

But Frank argues passionately against ‘the myth’ that chrysotile is a safe form of asbestos. In a recent review, he noted that approximately 10–12% of deaths among building insulator technicians are due to mesothelioma, a type of cancer that develops in the thin layer of tissue – the mesothelium – which covers many of the internal organs, including the lungs and the chest wall. He says the asbestos industry and users of asbestos have used public relations and paid scientists to muddy the waters.6

In the US, asbestos-related litigation continues and total payments are in the tens of billions of dollars. ‘The companies put

up a fight in most cases, delaying settlement until practically the eve of trial and disputing everything they can as to medical diagnosis and causation, and evidence of the plaintiffs’ exposure histories,’ says Barry Castleman, environmental consultant, who has spent 40 years working on asbestos as a public health problem.

Manmade substitutes for asbestos-based construction materials are available. For over 50 years, asbestos was combined with cement in Europe because its fibres are mechanically strong and durable, says Eshmaeil Ganjian, professor of civil engineering materials at Coventry University, UK. The resulting boards were used for internal and external walls as well as for roofs. Europe now uses polyvinyl alcohol (PVA) in its cement boards, he says, but this is more expensive than asbestos, which has come down in price over the past 20 years.

Ganjian is currently working on a project aimed at replacing asbestos

in cement boards in Iran with waste plant fibres, such as Kraft pulp, and polymeric fibres such as acrylic and polypropylene fibres. ‘The idea is to use locally available fibres, so we use cheap acrylic fibres available from petrochemical companies in the region. The strength of cellulose fibres is lower than asbestos fibres, but when we add polypropylene or acrylic or other synthetic fibres then this increases the mechanical strength,’ Ganjian explains.7

The Iranian government subsequently stopped importing asbestos from Russia and banned its use in cement board factories, switching to local alternatives. ‘This was a win-win situation. It saves lives and also uses a waste material,’ says Ganjian.

Ganjian now goes to conferences

and tells people from developing countries that there are alternatives to asbestos and it doesn’t have to be costly to make the change. He is currently co-supervising a PhD student at the Bogota University in Columbia who is working to replace asbestos in a local cement factory with cellulose fibres from bamboo waste. Other replacements for asbestos in fibre cement boards he is exploring include limestone powder8 and glassy granulated slag from iron furnaces.9

Meanwhile, the drive to ban the use of asbestos globally continues. At the Chemical Review Committee of the United Nations Environment Programme in Geneva earlier in 2017, the Canadian government announced that it would support the listing of chrysotile fibres in the Rotterdam Convention. This convention promotes open exchange of information and proper labeling of hazardous chemicals. Previously, Canada along with Kyrgyzstan, Kazakhstan and Ukraine had refused

World Health Organization (WHO) estimates that in a single year over 100,000 deaths are due to asbestos-related diseases. A recent estimate, based on an analysis of 79 behavioral, occupational and environmental and metabolic risks in 188 countries, funded by the Bill & Melinda Gates Foundation, put the figure closer to 200,000/year.3

‘The truth is that it is a nasty, hazardous, toxic carcinogenic material that has made millions and millions of people sick,’ says Arthur Frank, professor of environmental and occupational health at Drexel University School of Public Health in Philadelphia, US. Frank is a longtime advocate for banning the mineral.4

To date, around 60 countries have banned the use of asbestos, including the UK. Russia, India and China, however, still use asbestos in a range of products. The US is the last holdout among developed countries not to ban asbestos entirely. More significant for Western countries are the millions of tonnes of asbestos left in buildings – asbestos becomes a problem if disturbed, especially if the fibres go undetected.

Traditionally, those who work in the building trade are most at risk, though workers can bring home fibres on their clothes and this poses a risk to anyone they come in contact with. ‘There is a significant amount of data that points to as little as one day of exposure being sufficient to give rise to malignancy in humans and animals,’ says Frank. It’s unclear precisely the cellular mechanism, with health experts, he says, adding that asbestos causes lung and laryngeal cancer and possibly ovarian, gastro-intestinal and other cancers. In the UK, asbestos is responsible for half of work-related cancer deaths.5 No amount of asbestos is considered safe by public health experts.

The European Parliament has pushed for the removal of asbestos from all public buildings by 2028. The asbestos industry, however, argues that it is wrong to say that any exposure to asbestos can kill and believes there is a permissible level of exposure. In addition, the International Chrysotile Association, which represents producers of asbestos and is currently based in Canada, argues that chrysotile-type

References1 Annals Global Health, 2014,

80, 2572 Ann. Rev. Public Health, 2013,

34(1), 2053 Lancet, 2015, 386, 22874 Environmental Health

Perspectives, doi:10.1289/ehp.1002285

5 Occupational and Environmental Medicine., doi:10.1136/oem.2007.037002

6 Environmental Health Perspectives, doi:10,1289/ehp.1002285

7 Materials Today, doi.org/10.1016/j.matpr.2016.01.023

8 Construction and Building Materials, 2013, 46, 142

9 14th International Inorganic Bonded Fiber Composites Conference, Da-Nang, Vietnam, 2014

2m tEstimated amount of asbestos that continues to be used each year globally

200000Number of deaths in a single year due to asbestos-related diseases

Europe now uses polyvinyl alcohol (PVA) in place of asbestos in cement boards

‘The truth is that it [asbestos] is a nasty, hazardous, toxic carcinogenic material that has made millions and millions of people sick’

Arthur Frank Drexel University School of Public Health, Philadelphia, US

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to allow these fibres to be added to the convention. Nevertheless, consensus was not reached at Geneva, so chrysotile remains outside the Convention. And, as Castleman notes: ‘Listing under the convention would only require that there be notice and approved shipment prior to the international transport of chrysotile asbestos. It does not stop trade or ban its use. It

amounts to little more than putting health warning labels on the product.’

The legacy of asbestos and, crucially, its detection remain (see above). A portable detection device developed by researchers at Hertfordshire University, UK could, however, just be what the construction industry in both developing and developed countries need right now.

UK company, Alert Technologies is making a portable detector for airborne asbestos fibres. Prototypes are expected to be distributed later in 2017.

‘Asbestos has been banned in the UK since around the year 2000, but we have a legacy that has built up,’ explains Alan Archer, CEO of Alert Technologies. The portable device is designed to offer real-time warning of the presence of airborne fibres and the plan is to have some units priced so that contractors and construction workers can have it onsite.

Asbestos fibres are not dangerous in a solid state, but there is believed to be no safe level once they are airborne. ‘I ran a plumbing and heating company in south Devon and we were always coming across asbestos,’ says Archer. ‘I had several friends and colleagues who died because of exposure to asbestos. Detection was the problem.’

Until now, detection of asbestos fibres has been a labour-intensive process that requires sophisticated analytical equipment. An electron microscope is used to measures the shape and size of the sample’s fibres, and an X-ray diffraction unit is used to confirm the presence of asbestos.

The initial research that led to the development of handheld detector was done by Paul Kaye and his group at the University of Hertfordshire, UK, in the 1990s, and had nothing

to do with asbestos. Kaye was leading the Hertfordshire group in a series of research projects, including several funded by the UK Met Office, that aimed to determine the shape and size of particles in cirrus clouds by measuring the scattering of laser light. ‘Any particle that passes through a laser beam will scatter the light and that scattering pattern can tell you a lot about the shape, the size, and the orientation of the particle,’ says group member Chris Stopford. In addition, asbestos is unique among mineral fibres in rotating itself to align to a magnetic field. ‘We measured an airborne fibre with a laser beam as it flows through the device and then exposed it to a magnetic field, and mea-sured it again. If it rotated, we could be fairly confident that it is asbestos,’ says Stopford. This is due to the crystalline structure and inclusion of iron atoms in the molecule.

The researchers were keen to commercialise their technology in the 1990s, but the cost of lasers and computing power was prohibitive. Nevertheless, they did file a patent on the technology, and by the time Archer discovered the patent, the costs of lasers

and computers had dropped. With funding from the EU, Alert Technologies has turned the concept into a commercial product. ‘The results you get back using other methods take hours or days,’ says Archer,

‘whereas we can confidently identify in real time

airborne fibres and distinguish asbestos fibres.’

Alert Technologies

recently raised £700,000 and has launched a second investment round to bring that figure up to £1m.

The first line of portable products will be aimed at professional

surveyors and asbestos removal

contractors. The company has attracted interest

from oil companies and industrial plants, as well as from

companies interested in the decommissioning of

nuclear power stations.In addition, Archer says:

‘The fire service has also expressed an interest, as have the police, the military and the construction trade. There is an endless list of sectors that come across asbestos.’ They could even be used during refurbishment of prestigious buildings such as the Houses of Parliament and Buckingham Palace. The company plans to develop a hand-held model next.

PORTABLE DETECTORS ON THE WAY

~60Number of countries that ban the use of asbestos, including the UK. Russia, India and China still use asbestos in a range of products.

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